<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>第一次使用HTML</title>
</head>

<body>

    <h1>Hello world</h1>
    <h1>你好,世界</h1>
    <button style="background-color: pink;font-weight: bolder;" onclick="alert('什么玩意')">点击事件</button>

</body>

</html>